Improvement in hydraulic elevators



E. BREWER.

- HYDRAULIC ELEVATOR.

No. 189,424. Patented April 10, 1877.

X/Vilrqesaes.

N.PETFRS| PHOIG-LITHOGRAPH ER. WASHINGTON I! C UNITED STATES PATENTOFFICE.

ELIAS BREWER, OF BOSTON, MASSACHUSETTS.

IMPROVEMENT IN HYDRAULIC ELEVATORS.

Specification formin g'part of Letters Patent No. 189,424, dated April10, 1877; application filed January 10, 1877.

sufficient of an elevator to illustrate this invention. The cross-head ais provided with two sets of sheaves, b 0, arranged in recesses d e.Other sets of sheaves, fg, are arranged on stationary shafts in brackets11 j, between the 'cylinders. Two'ropes, lm, extend over these sets ofsheaves, as shown in the drawings. One end of each rope is connectedwith some stationary part of the elevator, and the other end with theplatform of the car in any usual way. Instead of placing the sheaves atthe ends of the cross-head, as usual, and

" lifting the cross-head by means of a central piston, therebysubjecting the cross-head to great strain at its center, the cross-headis arranged to be positively lifted at each end with equal force, bymeans of independent cyl inders and pistons of equal size, and inaddition to these two cylinders a central piston,

I connected with the cross-head, operates within a central cylinder,having connection with the main in such manner that the water in thecentral cylinder, acting upon the head of the central piston, serves asa counter-balance sub,-

stantially for the weight of the car, the water in the central cylinderre-entering the main when the car descends.

The piston-rods n 0 secured to the ends of the cross-heads enter thecylinders 11 q, to be connected by pipes, as at 1' s, with the main t. Athree-way orother suitable cock will be used at u'to admit water intothe cylinders to raise the pistons and car, and as the car falls thecock will permit the discharge of the -water through a pipe, w, into thesewer.

Attached at or near the center of the crosshead is a piston, 41:, fittedto a cylinder, y.

This piston and cylinder, situated at the cenlow the central piston.

ter of the cross-head, assist in keeping the strain even thereon, andacts as a counter-balance for the weight of the car. The water will'flow into the cylinder from the main, through a branch, as at a as thecar rises, and as it descends the water will be forced by the weight ofthe car back again into the main.

Instead of forcing the water back into the main it may be forced backand'upward into a suitable tank, and when the cross-head isagain raisedthe water from the tankwill fol- In this way the water for the centralcounter-balance may be used over and over. This plan permits the savingof water.

I do 'not claim the use of two cylinders, one lifting at each end of thecross-head, nor do I, broadly, claim the use of a car-counterbalancingcylinder containing water in connection with an elevator. In someinstances I propose to employ a three-armed or cross-shaped cross-head,and with them use either three or four pistons and cylinders; but in allcases the centrally-placed car-counterbalancing cylinderwill beemployed.

The outlet of the cylinder 3 will be of proper size to permit thedescent of the car at the desired speed. By means of three cylinders themovement of the car is rendered very steady, and as the ropes andsheaves are arranged it is impossible to detach the ropes from thesheaves, should the car be obstructed, as now happens in the class ofelevators wherein the sheaves are at the outer ends of the cross-heads.

In this invention it is deemed necessary to always use two ropes, andtwo sets of sheaves for each rope, each rope and its set of sheavesbeing arranged aside from the center of the cross-head. The pistons areall connected positively with the crosshead, and always move togetherand with the cross-head each, 4

time that the car rises and falls.

Guides for the cross-head are considered unnecessary. Bearing portions amay be applied at the upper ends of the cylinders to steady the outersides of the piston-rods.

I claim- The cross-head, its two sets of sheaves, and two equal pistons,positively attached at the In testimony whereof I have signed my name tothis specification in the presence of two subscribing witnesses.

ELIAS BREWER. Witnesses:

Gno. W. GREGORY, W. J. PRATT.

